Thank you for your prompt assistance. But surely this discrepancy can't be correct because if you check the continuing example in the attachment, you would see the authors get an R1 = 1.45kΩ and R2 = 3.55kΩ.

If I calculate using the same equation as before but now with 5kΩ I would get R1 = 2.556kΩ and R2 = 2.444kΩ.

Thanks for your input Jony130. That is the value I got but apparently the authors got different R1 and R2 values for both of these examples. The first example differed only slightly while the second example is by a landslide.